September 2016

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September 2016

Average surface air temperatures for September 2016

Surface air temperature anomaly for September 2016 relative to the September average for the period 1981-2010. Source: ERA-Interim. (Credit: ECMWF, Copernicus Climate Change Service) Download the original image

September 2016 was warmer than the 1981-2010 average over most of Europe. The month was especially warm over northern Germany and southern Scandinavia. Temperatures were below average over south-western Russia, but substantially above average over north-western Russia and much of Siberia. Elsewhere, September temperatures were above average over most land and ocean areas. Regions with markedly above-average temperatures include the Arctic Ocean, the north-eastern Pacific Ocean, eastern Iran, the south-eastern USA and offshore of much of Antarctica.

Temperatures were below average along the equator over the eastern Pacific Ocean, indicating weak La Niña conditions, over some oceanic regions of the southern hemisphere and over part of the North Atlantic. Over land, temperatures were well below average over much of Australia and Antarctica, and a little below average in several other places.

Surface air temperature anomaly for the 12 months ending September 2016 relative to the average for 1981-2010. Source: ERA-Interim. (Credit: ECMWF, Copernicus Climate Change Service) Download the original image

Average temperatures for the twelve-month period ending in September 2016 were:

most above the 1981-2010 average over the seas to the east of Svalbard;

higher than average over most areas of land and ocean, including the tropical eastern Pacific Ocean associated with the El Niño event that peaked there in November 2015;

lower than average over parts of the Antarctic and southern oceans, the northern Atlantic Ocean and the north-western Pacific Ocean.

Monthly global-mean and European-mean surface air temperature anomalies relative to 1981-2010, from January 1979 to September 2016. The darker coloured bars denote the September values. Source: ERA-Interim. (Credit: ECMWF, Copernicus Climate Change Service)Access to data Download the original image

September 2016 extended the spell of exceptional global warmth that has now lasted more than a year. Although the global temperature anomaly peaked in February and declined steadily from March to June, it rose again in July and August, and dropped only a little in September. The global average temperature anomaly for September was:

0.56 OC higher than the September average for 1981-2010;

0.11 OC higher than the previous highest September value, which occurred in 2015.

With the exception of June 2016, each month from October 2015 to September 2016 has been more extreme than January 2007, which was previously the month with the warmest anomaly (0.54OC). Each month from August 2015 onwards has been the warmest on record for that particular month.

The largest anomalies in European-average temperatures occur in wintertime, and values can vary substantially from month to month. The anomaly for September 2016 was 1.4 OC, only about 0.2 OC lower than the largest September value, which occurred in 2011.

Running twelve-month averages of global-mean and European-mean surface air temperature anomalies relative to 1981-2010, based on monthly values from January 1979 to August 2016. The darker coloured bars are the averages for each of the calendar years from 1979 to 2015. Source: ERA-Interim. (Credit: ECMWF, Copernicus Climate Change Service)Access to data Download the original image

Averaging over twelve-month periods smooths out the shorter term variations. Globally, the period from October 2015 to September 2016 is the warmest twelve months on record, with a temperature 0.64OC above the 1981-2010 average. The corresponding value for the twelve months of 2015 is 0.44OC. The warmest previous calendar year, 2005, had a temperature anomaly of 0.35 OC.

Uncertainty in the global value is relatively high for the year 2005, but there is agreement between various datasets regarding:

the exceptional warmth of 2016, and to a lesser extent 2015;

the overall rate of warming since the late 1970s;

the sustained period of above-average values from 2001 onwards.

There is more variability in average European temperatures, but values are less uncertain because observational coverage of the continent is relatively dense. Twelve-month averages for Europe have been at a persistently high level for the last three years. They are nevertheless lower than averages from around the middle of 2006 to the middle of 2007.